I'm starting to think that Big D has a seriously subpar HR department.

The Devil literally picked her out (and up) himself. She went from exotic dancer to Devil employee with as far as we know, no intervening training of any sort. She's probably not evil at all in any meaningful sense of the term; whatever the qualifications might be for being an exotic dancer, evil isn't one of them. One can only presume that The Devil doesn't really care one way or the other if his employees are evil per se, just as long as they do their jobs.

Besides, he didn't tell her to destroy them, just to get rid of them. She could return them to the manufacturer, drop them off at a pet shelter or a garage sale, set them free into the wild, it's all the same to him. Heck, she could keep them in her room and as long as they stay in there, she'll still have gotten rid of them as far as The Devil is concerned. It's hardly her fault that he wasn't more specific.